PELTATE, shield-like, fixed to the stalk by a point within the margin; peltate hairs, attached to their middle. PENDULOUS, applied to ovules which are hung from the upper part of the ovary. PENICILLATE, resembling a camel’s-hair pencil. PENNI-NERVED, and PENNI-VEINED, the veins disposed like a feather, running from the middle of the leaf to the margin. PENTAMEROUS, composed of different whorls in five, or multiples of that number. PEPO, the fruit of the melon, cucumber, and other _Cucurbitaceæ_. PERENNIAL, living, or rather flowering, for several years. PERFOLIATE, a leaf with the lobes at the base, united on the side of the stem opposite the blade, so that the stalk appears to pass through the leaf. PERIANTH, a general name for the floral envelopes; applied in cases where there is only a calyx, or where the calyx and corolla are alike. PERICARP, the covering of the fruit. PERICHÆTIAL, applied to the leaves surrounding the fruit-stalk or seta of mosses. PERICLADIUM, the large sheathing petiole of _Umbelliferæ_. PERIDERM, a name applied to the outer layer of the barks. PERIDIUM, the envelope of the fructification in gasteromycetous fungi. PERIGONE, same as Perianth. Some restrict the term to cases in which the flower is female, or pistilliferous. It has also been applied to the involucre of _Jungermannieæ_. PERIGYNOUS, applied to the corolla and stamens when attached to the calyx. PERIGYNUM, applied to the pistil in the genus _Carex_. PERIPHERICAL, applied to an embryo curved so as to surround the albumen, following the inner part of the covering of the seed. PERISPERM, the albumen or nourishing matter stored up with the embryo in the seed. PERISTOME, the opening of the sporangium of mosses after the removal of the calyptra and operculum. PERITHECIUM, a conceptacle in cryptogams, containing spores, and having an opening at one end. PERSISTENT, not falling off, remaining attached to the axis until the part which bears it is matured. PERSONATE, a gamopetalous irregular corolla, having the lower lip pushed upward, so as to close the hiatus between the two lips. PERTUSE, having slits or holes. PERULÆ, the scales of the leaf-bud. PETALOID, like a petal. PETALS, the leaves forming the coralline whorl. PETIOLATE, having a stalk or petiole. PETIOLE, a leaf-stalk; _Petiolule_, the stalk of a leaflet in a compound leaf. PHÆNOGAMOUS, same as Phanerogamous. PHANEROGAMOUS, having conspicuous flowers. PHYCOLOGY, the study of _Algæ_, or sea-weeds. PHYLLARIES, the leaflets forming the involucre of composite flowers. PHYLLODIUM, the leaf-stalk, enlarged so as to have the appearance of a leaf. PHYLLOTAXIS, the arrangement of the leaves on the axis. PHYSIOGNOMY, general appearance, without reference to botanical characters. PHYSIOLOGY, vegetable, the study of the functions of plants.